Ion, plus the local geographic frame (n-frame) is utilized because the reference navigation frame in non-polar regions. The e-frame might be used for continuous worldwide navigation. However, mainly because the e-frame adopts Cartesian coordinates, the height channel is coupled with 3 rectangular coordinates but this causes position errors to diverge rapidly and brings issues to damping filtering. Additionally, the e-frame will not have an explicit azimuth, which isPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Copyright: 2021 by the authors. Licensee MDPI, Basel, Switzerland. This short article is definitely an open access report distributed beneath the terms and circumstances with the Inventive Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Appl. Sci. 2021, 11, 9572. https://doi.org/10.3390/apphttps://www.mdpi.com/journal/applsciAppl. Sci. 2021, 11,two ofinconvenient for flight route organizing. Ordinarily, the INS/GNSS integrated navigation program requires the neighborhood geographic frame as the navigation frame at low and middle latitudes and turns as an alternative to grid frames at high latitudes. When the navigation frame is switched in between distinctive coordinate frames, for example the Benfluorex supplier G-frame and n-frame, the structure of the filter alterations. Within this case, as a further study [11] points out, if the consistency with the error state estimation can’t be assured, this can cause the integrated navigation filter to overshoot and trigger error discontinuity. Nevertheless, the present research [124] on polar region navigation mainly focuses on the design and style of an integrated navigation algorithm within the polar area or on hunting for any navigation frame to achieve worldwide navigation independently and to prevent the problem caused by switching in between navigation frames. 1 study [15] proposed the virtual sphere n-vector algorithm and derived detailed mechanization and dynamic equations. Their virtual sphere n-vector algorithm utilized the surface typical vector of your ellipsoid model to represent the aircraft’s position, and didn’t have particular mathematical singularities. Basically, the virtual sphere n-vector algorithm would be the similar because the e-frame algorithm and its azimuth definition is indistinct. The researchers of [11] and [16] proposed a hybrid polar navigation technique, which accomplishes the CC-115 Description inertial navigation mechanization within the e-frame, whereas it outputs the navigation parameters in the G-frame or t-frame. Additionally, the research of [11,16] introduce a position matrix to decouple the height channel and 3 rectangular coordinates, which can resolve the problem of position error divergence. In this way, the continuity of global navigation is guaranteed. However, it absolutely adjustments the navigation frame of your present airborne inertial navigation technique, which can be not conducive to technique upgrades. Papers by [17,18] both proposed indirect polar navigation methods, applying a combination of your wander frame and G-frame or the t-frame to attain smooth switching of navigation frames. Nevertheless, indirect polar navigation techniques didn’t fundamentally solve the filter consistency issue during the coordinate frames switching. To be able to solve the problem of filter discontinuity caused by the transform of navigation frame, this paper proposes a polar-region airborne INS/GNSS integrated navigation strategy, based on covariance transformation. The transformation partnership involving the system error sta.
